This invention relates to safety valves, and particularly to a normally open valve that will shut in the event of an earthquake or the like. In the event of an earthquake or any like catastrophy such as an explosion or the like, fluid supply lines under pressure and gas lines especially become very dangerous sources of combustible fluid. Heretofore, numerous gravity operated safety valves have been proposed, but they have not been acceptable for one reason or another; mainly because of impracticality due to improper sensitivity and non-reliability. Ball valves have been perched in various ways, subject to being shaken from a normally open position so as to drop into a seated position, thereby shutting off fluid flow. These ball valves have been both tethered and free, and they have been resettable, and they have been positioned at both the negative and positive pressure sides of the fluid flow. It is a general object of this invention to improve upon the prior art and to provide a reliable and acceptable safety valve of the type under consideration, and namely a safety valve which has all of the desirable features of the prior art incorporated therein.
An object of this invention is to provide a normally open valve subject to closure when shaken. This valve is normally open to the pressure regulated flow of utility gas into a building, and therefore is in the downstream side of a pipe line flow pressure regulator. Accordingly, this safety valve is subject to low gas pressure, and in practice it is subject to moderate flow velocities. In practice, the low pressure gas at moderate velocity enters a voluminous chamber, so as to flow around the normally open position of the ball valve therein without disturbing the same.
It is an object of this invention to provide a ball valve seat which provides a pedestal for predictable and reliable operation of the ball valve. It is also an object of this invention to provide such a pedestal that is subject to release of the ball valve when subject to excessive motion on any one of its x, y and z axes. It is still another object of this invention to provide a pedestal support for a ball valve of the type under consideration and which is in the form of a machined insert formed with precision by but few and only several machining operations.
It is essential that the safety valve of the present invention be installed in a utility pipe line from a gas meter or the like, and that it be perfectly horizontal in its installed operative condition. Therefore, it is an object of this invention to provide a simple leveling means associated with the gas flow chamber and the provision of a valve seat for the positive shut-off of gas flow, a check valve, in the case of an emergency situation that is earth shaking.